Good question ! I just voted "same as actually" because I would prefer (later, season 3...) fixed storages for players in stations, I explain my view:
First, by having 600/200 you can wait a little bit before cleaning your (bag). Two, you must choose, decide, accepting idea you cannot have all things at same time. These days I am not full but I limit numbers of low rate materials (40 --> 30 --> 25) I can find everywhere, when I am near 500/150.
I think that if players ask dev's to upgrade (bag) sizes today, It will be harder for them to ask for new storages in stations later. This point of view is not important now, but I know how it is hard to retire materials just because you move from a big cargo ship (trading, mining) to a fighting ship (with small cargo inside just helping to upgrade it with engineers). You can answer that limitations you speak about don't concern the cargo storage, but the (bag) you always keep with you when you move from ships to ships. I just consider that having a bigger size in the bag could limit later possibility to have fixed containers (cargo + bag) in stations. In two words: I really prefer ask now for fixed storages in stations than having bigger capacity on me.
To finish, I think numbers allowed 600/200 are enormous when I take a look to my pockets in the cockpit.
Fly safe o/